Late-inning pressure situations are defined as any at-bat in the seventh inning or later where the batter's team trails by three runs or fewer, is tied or is ahead by only one run. If the bases are loaded and the batting team trails by four runs, this also counts as a late-inning pressure situation.
There is much debate among people within baseball regarding "clutchness" and how to determine whether certain hitters or pitchers are clutch. LIPS is one way of doing so, although it can be highly unreliable because the sample sizes are often small, and because not all late-inning pressure situations are equal when it comes to determining how clutch a player is.
LIPS was developed by the Elias Sports Bureau in 1985 in an attempt to answer the question, "Do clutch hitters exist?"
Watch: Brett Gardner comes through in a late-inning pressure situation.